Signal Detection for Ultra-Massive MIMO: An Information Geometry Approach
Jiyuan Yang, Yan Chen, Xiqi Gao, Dirk Slock, Xiang-Gen Xia
TL;DR
This work tackles the challenging problem of signal detection in ultra-massive MIMO, where MAP/ML detectors are NP-hard. It introduces an information geometry-based SD (IGA-SD) that recasts posterior marginals as an exponential-family problem and computes them via iterative m-projections between an independent objective manifold and interacting auxiliary manifolds, using Lyapunov CLT to obtain tractable Gaussian approximations. The resulting MPM detector relies on approximate a posteriori marginals p_k(s_k|y) with updates guided by the natural parameters on an embedded e-flat manifold, achieving a per-iteration complexity of $O(16 N_r K (L+1))$ and competitive BER performance. Simulations across 4-, 16-, and 64-QAM demonstrate that IGA-SD can outperform LMMSE, AMP, and EP with fewer iterations, indicating strong potential for scalable, efficient detection in future ultra-massive MIMO systems.
Abstract
In this paper, we propose an information geometry approach (IGA) for signal detection (SD) in ultra-massive multiple-input multiple-output (MIMO) systems. We formulate the signal detection as obtaining the marginals of the a posteriori probability distribution of the transmitted symbol vector. Then, a maximization of the a posteriori marginals (MPM) for signal detection can be performed. With the information geometry theory, we calculate the approximations of the a posteriori marginals. It is formulated as an iterative m-projection process between submanifolds with different constraints. We then apply the central-limit-theorem (CLT) to simplify the calculation of the m-projection since the direct calculation of the m-projection is of exponential-complexity. With the CLT, we obtain an approximate solution of the m-projection, which is asymptotically accurate. Simulation results demonstrate that the proposed IGA-SD emerges as a promising and efficient method to implement the signal detector in ultra-massive MIMO systems.
